Nova sr Head gasket

[sr nova boi]

Hi all, the head gasket recently went on my 1.4 sr nova, I have bought new gaskets for it and plan to get the head skimmed. I was wondering while the head is off is there anything I can do to increase the engines performance? The engine is standard at the moment with 80,000 genuine miles on it and was running well prior to the head gasket failing! Also I have a set of twin webber 40s to go on, and I want to uprate the cam but am unsure of which one? Any help will be appreciated, thanks, Rob

Also has anyone got a diagram of how twin 40s would fit to this engine? Thanks

[C612DNM]

As it's the 1400, you need the correct manifold for the job. The port shape is different from the 1300.

You need the alternator bracket that drops it out of the way, otherwise it fouls the bottom of the carb. You *might* need a longer adjuster for the alternator, and a different drive belt.

Your standard fuel pump is more than enough, if the 40's have the right plumbing, there's a return line via a T-piece.

Fitting twin 40's, then getting them jetted correctly, will provide you with the biggest single increase in power in one hit, taking the 70ish HP you have not, up to 90ish.

Cam upgrade - Kent AST2 - use factory followers - not the uprated heavy duty ones (if they break, the nose comes off, the remnants of the follower press down on the spring retainer, the collets come out, the valve drops, your engine goes to lunch) - and preferably use new lifters.

Use ITG Megaflow or Pipercross foam filters with short ram pipes to reduce the stand-off from the carbs.

Remember - get it rolling roaded!!

Enjoy.

[Jon_nova1]

If your getting the head skimmed anyway why not get it skimmed to get higher compression?

[C612DNM]

Because your engine is designed to run on 95RON guzzoline, and just raising the compression ratio will not gain you much.

Increasing the ratio on it's own isn't worth much in terms of power. Couple it up with cam, head gasflow, etc... then you're there. 10:1 and you need 97RON (because they don't make 96RON!) or it'll detonate to bits when the timing is peaked.

Been there, printed, sold, and worn out the T-shirt.

[craig green]

You'll only retard the ign to avoid the pinking from higher CR. pointless really.
If you have the time & money, head porting & bigger inlet valves is a worthy mod whilst the head is off.

[C612DNM]

+1

Blydenstein B+

If you can find one.

[Stuart]

T40's alone worth 20bhp on a 100% bog std 1.4 8v............ I'll have some of that crack your're smoking lol

Might see 10hp, and then the full 20 with a cam imho.

esp as the bottom end is likely to be tired.

[Sloth]

also, tescos 99 octane is regularly voted best fuel. and our lasses jap map celica likes it. if it was me id start with a 1600, and then webbers b++ head cam etc.

[Stuart]

10:1 isnt really high anyway... its pretty low CR imho. 12:1, now thats high :)

[Sloth]

22:1, and direct injection, with some derv, now were talking....

[Stuart]

in that game 22:1 is a bit low too :lol:

[Sloth]

srsly? i did hear of a perkins running 30:1, thought 22 was bout right.

[Stuart]

lows 20's are common place and some fun development is being played with around the high 20's low 30's

[C612DNM]

T40's alone worth 20bhp on a 100% bog std 1.4 8v............ I'll have some of that crack your're smoking lol

Might see 10hp, and then the full 20 with a cam imho.

esp as the bottom end is likely to be tired.

Vauxhall Nova 1.3SR 70hp
Vauxhall Nova Sport 93hp

Errr... 23hp. Want some crack now?

That's with 28mm chokes in the 40's. Go to 32's and while you'll lose some torque, you'll win a few more HP.

And with some 30mm full radius ram pipes and foam filters, maybe a few more too, over the Irmscher air filter setup.

Bottom end tired? Not necessarily. Loose and stress relieved.

Diesel compression ratios - the high figures you give as "playing with" are often found in indirect injection engines, which are far from efficient. Take the Audi R10 TDi, which runs with a 16.5:1 compression ratio - lower than that of many road engines.

22:1 again, an indirect engine. Modern Di's are in the 16-18:1 region.

Scania's 730hp Euro 5 engine runs at 17.4:1

Tractor Pullers, often the most seriously tuned diesels to breath smoke, run around 12:1 compression ratios, simply so they can cope with double and triple stage turbo/supercharging.

I look forward to some more of your high velocity trifle.

[Sloth]

actually the 22:1 was from a toyota direct injection engine mate. as for the rest, i'll get the popcorn....

[Stuart]

note where I said bog std 1.4 8v ;) eg the hideous square ported waste of space head... not the great 1.3 one :p.... its fairly easy to see how a 1.3 could make more power with a decent inlet tract. But the 1.4, hmmmmm throw the square port head away and fit the 1.3 or mpi head and yes youre laughing (one CR is adjusted to suit whatever needs you have).


of course comparing small 4 cylinder engines to truck/race engines is a great/fair thing to do lol you carry on sweety

[mowgli]

22:1 cr on a 10 litre engine running at 1500 rpm with a turbo the size of a bucket will give 1million trouble free miles and 450hp...or what a turbo was really invented for....

ps. everyone knows my views on head skimming.....

1. is the head pitted?
y. then skim it
n. clean it up & re fit it.

2. get the valves out & re lap the seats & swap the seals.

[Sloth]

22:1 on a 2.0 toyota car engine...

[mowgli]

ok, so it took car makers 25 years to catch up with heavy diesel engine manufacturers, its a pity they are obsessed with trying to make a td engine that works just like a petrol one. cos a slow revving diesel engine with a decent variable transmission (think daf) would create a fantastically efficient yet quick car...

good td car 65mpg ave, weight 1.4t,
lorry, 8.5mpg, weight 44t

[C612DNM]

I forget, of course, Toyota have this fixation with high compression diesels, where Honda and Nissan (who make some of the cleanest most efficient small derv burners on the planet) stick to the given rule of Direct Injection engines that puts the CR between 16 and 18:1

When Toyota make a decent engine, I'll agree with them.

Agreed Mowgli - steady plodder with humungous torque and a CVT makes for great acceleration.

Back to the thread - the 1.4 square port thing can produce the power when given the WBB treatment. It's a cleaner burn engine design, which came about when the tree huggers demanded cleaner engines and crapalytic converters